Field of the Invention
The present invention relates to an inkjet print device and an inkjet head ejection performance evaluation method, and particularly relates to an inkjet print device using an inkjet head which has a plurality of nozzles arrayed in a matrix and a technology for evaluating ejection performance of the inkjet head.
Description of the Related Art
Japanese Patent Application Laid-Open No. 2008-012701 has described an inkjet print device which includes an elongated liquid droplets ejection head having a plurality liquid droplets ejection units arrayed in a width direction of a paper sheet, each liquid droplets ejection unit having a plurality of nozzles arrayed in a matrix and aligned in a row in a conveying direction of a paper sheet. Japanese Patent Application Laid-Open No. 2008-012701 has proposed a method for adjusting an attaching angle of a liquid droplets ejection head by detecting a displacement amount of the attaching angle in a rotation direction along a recording surface of a paper sheet for each liquid droplets ejection unit.
According to Japanese Patent Application Laid-Open No. 2008-012701, a line pattern is printed by the liquid droplets ejection head, a printed result thereof is read by an optical sensor to obtain read image data, from which a gap between adjacent lines is calculated, and the displacement amount of the attaching angle for each liquid droplets ejection unit is calculated based on the calculated line gap (claim 7, paragraph 0044 in Japanese Patent Application Laid-Open No. 2008-012701). The “paper sheet” in Japanese Patent Application Laid-Open No. 2008-012701 is a term corresponding to a “recording medium” herein, and the “liquid droplets ejection unit” in Japanese Patent Application Laid-Open No. 2008-012701 is a term corresponding to “inkjet head” herein.
Japanese Patent Application Laid-Open No. 2014-226911 has described a configuration in which a linear pattern formed by an inkjet head on a paper sheet is read by a scanner to obtain information, from which positional information on each linear pattern is obtained to calculate an inclination angle of the head (claim 1, paragraphs 0046-0047 and 0049-0055 in Japanese Patent Application Laid-Open No. 2014-226911). The “linear pattern in “Japanese Patent Application Laid-Open No. 2014-226911 is a term corresponding to the “line pattern” in Japanese Patent Application Laid-Open No. 2008-012701.
Japanese Patent Application Laid-Open No. 2012-133582 has described a technology in which a linear test pattern is formed by nozzles and a read image of the test pattern is analyzed to detect a defective ejection nozzle.